CODEWITHSUNDEEP
clojure
Conan
Conan

Reputation: 2358

Idiomatic way to get from nested structures in Clojure

Which of these is more idiomatic Clojure?

(def book {:title "Joy of Clojure" 
           :authors ["Michael Fogus" "Chris Houser"]})

(get-in book [:authors 0])
;; => "Michael Fogus"

(-> book :authors first)
;; => "Michael Fogus"

When I have much more complicated data structures, this becomes more relevant. Presumably there's no technical difference between the two?

Upvotes: 2

Views: 212

Answers (1)

noisesmith
noisesmith

Reputation: 20194

get-in is better for nested structures, because many interesting keys are not callable, in particular indexes in a vector (other than first or second) or string keys in hash-maps.

user=> (get-in [{:a 0} 1 nil "unknown" {:b {"context info" 42}}] [4 :b "context info"])
42

Upvotes: 6

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